Fluid valves work by allowing and disallowing flow through the valve or, in the case of directional control valves, by directing the flow to alternating ports. In typical on/off valves there are three connection points: an input port where pressurized fluid is connected, an outlet port where fluid will flow when the valve is open, and an actuator connection point where a mechanical device causes the valve to open and close. Opening and closing of the valve can be accomplished via manual means, such as a home faucet, electrical means where an electrical signal actuates a solenoid, pneumatic means where compressed air (or gasses) actuate a diaphragm or piston, or hydraulic means where pressurized hydraulic fluid actuates a diaphragm or piston. In all of these cases the manual lever, electronic solenoid, pneumatic diaphragm or hydraulic diaphragm or piston move a part within the valve causing the valve to open or close. In all of these cases an external force or signal is required to make the valve switch between open and closed states.